Semiconductor Capping Layer Selective Etching for Air Gaps
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Solution Overview
Problem
The reduction in critical dimension of semiconductor devices increases electrical resistance and capacitive coupling between interconnection lines, making it difficult to achieve high-speed operation.
Innovation Solution
A method of forming a semiconductor device involves creating a capping layer with varying chemical compositions on both the metal pattern and insulating layer, allowing for selective etching to form recess regions and voids, which reduces parasitic capacitance and improves integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the critical dimension of semiconductor devices is reduced to achieve high integration, then the integration density is improved, but the electrical resistance of interconnection lines increases and capacitive coupling between lines increases
Solution Approach 1:
The patent introduces air gaps (voids) in the vertical dimension between metal interconnection lines. By creating three-dimensional space between conductors through recess regions, the design moves from a planar two-dimensional layout to a three-dimensional structure, reducing parasitic capacitance without increasing lateral pitch
Solution Approach 2:
The capping layer is formed with different chemical compositions in different regions: a first composition on metal patterns and a second composition on insulating layers. This local differentiation allows selective etching to create air gaps specifically between metal lines while preserving the capping layer over metal patterns, thereby locally reducing capacitance where needed without compromising overall structure
2Productivity
If the critical dimension of semiconductor devices is reduced to achieve high integration, then the integration density is improved, but the capacitive coupling between interconnection lines increases
Solution Approach 1:
The patent introduces air gaps (voids) in the vertical dimension between metal interconnection lines. By creating three-dimensional space between conductors through recess regions, the design moves from a planar two-dimensional layout to a three-dimensional structure, reducing parasitic capacitance without increasing lateral pitch
Solution Approach 2:
The capping layer is formed with different chemical compositions in different regions: a first composition on metal patterns and a second composition on insulating layers. This local differentiation allows selective etching to create air gaps specifically between metal lines while preserving the capping layer over metal patterns, thereby locally reducing capacitance where needed without compromising overall structure
3Ease of manufacture
If a capping layer is formed on both metal patterns and insulating layers, then selective etching can form recess regions, but the process complexity increases
Solution Approach 1:
The capping layer is formed with different chemical compositions in different regions: a first composition on metal patterns and a second composition on insulating layers. This local differentiation allows selective etching to create air gaps specifically between metal lines while preserving the capping layer over metal patterns, thereby locally reducing capacitance where needed without compromising overall structure
Solution Approach 2:
The patent changes the chemical composition parameter of the capping layer based on location. By depositing materials with different etch selectivities (e.g., metal nitride on metal, metal oxide on insulator), the process enables selective removal of the capping layer in specific regions, simplifying subsequent etching steps despite the added deposition complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces electrical resistance and capacitive coupling, enabling higher speed and integration capabilities in semiconductor devices by selectively etching the capping layer to form air gaps between metal lines, thus enhancing operational performance.
Implementation Method 1
The capping layer may include a first etch selectivity, with respect to the insulating layer, on the metal pattern. Moreover, the capping layer may include a second etch selectivity, with respect to the insulating layer, on the exposed portion of the insulating layer.
Data Source
AI summary
Methods of forming a semiconductor device are provided. A method of forming a semiconductor device may include forming a capping layer on a metal pattern and on an adjacent portion of an insulating layer, the capping layer comprising a first etch selectivity, with respect to the insulating layer, on the metal pattern and a second etch selectivity, with respect to the insulating layer, on the portion of the insulating layer. Moreover, the method may include forming a recess region adjacent the metal pattern by removing the capping layer from the portion of the insulating layer. At least a portion of the capping layer may remain on an uppermost surface of the metal pattern after removing the capping layer from the portion of the insulating layer. Related semiconductor devices are also provided.